1. Field of the Invention
The present invention relates to a punch press for performing press working, punch out working, forming working or the like on a plate-shaped workpiece.
2. Description of the Related Art
A conventional punch press will be briefly explained in the following manner.
The conventional punch press is provided with a press main body, and the press main body is provided with an upper frame and a lower frame opposed to each other in a vertical direction. An upper turret member provided with a plurality of attachable/detachable punches is arranged on the upper frame, and an lower turret member provided with a plurality of attachable/detachable dies is arranged on the lower frame so as to be opposed to the upper turret member in a vertical direction. A striker for pressing a predetermined punch from the above is provided above the upper turret member so as to be movable upward and downward and an ascending/descending hydraulic cylinder for ascending/descending the striker is provided in the upper frame.
Furthermore, for positioning the workpiece at a predetermined position between the upper turret member and the lower turret member, a carriage base extending in left and right directions (namely, a X-axis direction) is provided on the lower frame movably in forward and rearward directions (namely, a Y-axis direction), and a carriage is provided on the carriage base so as to be movable in the X-axis direction. Here, the carriage base is moved in the Y-axis direction by driving of a Y-axis motor, and the carriage is moved in the X-axis direction by driving of a X-axis motor.
Accordingly, the carriage is moved in the X-axis direction by driving of the X-axis motor and the carriage base is moved in the Y-axis direction by driving of the Y-axis motor under the state where the plate-shaped workpiece has been clamped by clampers, so that the workpiece is moved in the X-axis direction and the Y-axis direction, thereby positioning the workpiece at the predetermined position between the upper turret member and the lower turret member. Then, the striker is descended by driving of the ascending/descending hydraulic cylinder so that the predetermined punch is pressed from the above by the striker. Thereby, the predetermined punch and the predetermined die are caused to cooperate with each other, so that a press working can be performed on the workpiece. Incidentally, after the striker is descended, it is ascended and returned back to its home or original position.
The above operation is repeated so that a series of press workings can be performed on a workpiece.
However, in the course of performing press working on a workpiece, such a deformation as a bending, a warping, or the like occurs in a portion of the workpiece due to that the workpiece collides with a die or the like or the former is caught by the latter. In the course of performing the press working, particularly a press forming working, there occurs a case that the workpiece is pushed upward by a die and a deformation occurs on the workpiece in many cases. When a deformation of a workpiece becomes larger, a portion of the workpiece comes in contact with the upper turret member or the like. When the press working continues under, this contacting state, the upper turret member or the like which is a constituting element for a punch press is injured and the workpiece is caught between the upper turret member and the lower turret member. Therefore, the workpiece must be released from between the upper turret member and the lower turret member, which results in elongation of the working time.
The present invention has been achieved with such points in mind.
It therefore is an object of the present invention to provide a punch press which can be prevented from being continued to punch on a workpiece when the workpiece is in contact with an upper turret member of the punch press, thereby the upper turret member or the like which is a constituent element for the punch press can be suppressed from being injured.
To achieve the object, according to a first aspect of the present invention, there is provided a punch press comprising: a press main body; an upper turret member being arranged on the press main body, the upper turret member being provided with a plurality of attachable/detachable punches; a lower turret member being arranged on the press main body so as to be opposed to the upper turret member in a vertical direction, the lower turret member being provided with a plurality of attachable/detachable dies; a striker being provided above the upper turret member, the striker being movable upward and downward for pressing a predetermined punch from the above; striker ascending/descending means for ascending/descending the striker; a carriage being movable in a horizontal direction, the carriage being provided with a damper for holding a workpiece in order to position the workpiece between the upper turret member and the lower turret member; and carriage moving means to move the carriage in the horizontal direction, wherein the upper turret member comprises: a turret member main body; a workpiece detecting plate being provided at a lower portion of the turret member main body; and an insulating body which insulates the turret member main body and the workpiece detecting plate from each other; wherein one end of a first conductive wire is electrically connected to the workpiece detecting plate; wherein the damper and the carriage are electrically connected to the press main body; wherein one end of a second conductive wire is electrically connected to the press main body; wherein the other end of the first conductive wire and the other end of the second conductive wire are electrically connected to a touch detecting unit to detect a touch between the workpiece detecting plate of the upper turret member and a workpiece which is clamped by the clamper.
In the punch press according to the first aspect, under a state where a plate-shaped workpiece is clamped by the clamper, the carriage is moved in a horizontal direction by driving of the carriage moving means so that the workpiece is moved in the horizontal direction to be positioned at a predetermined position between the upper turret member and the lower turret member. Then, the striker is descended by driving of the striker driving means and a predetermined punch is pressed from the above by the striker. Thereby, the predetermined punch and a predetermined die are caused to cooperate with each other so that a press working can be performed on the workpiece. Incidentally, after the striker is descended, it is ascended and returned back to its home position. By repeating the above operations, a series of press workings can be performed on the workpiece.
When a portion of the workpiece comes in contact with the workpiece detecting plate while the series of press workings are being performed on the workpiece, it is detected by the touch detecting unit that the first conductive wire and the second conductive wire are made conductive to each other through the workpiece, the damper and the carriage. That is, it is detected by the touch detecting unit that a deformation such as a bending, warping or the like has occurred in the workpiece and a portion of the workpiece has come in contact with the workpiece detecting plate on the upper turret member.
Therefore, under the state where the portion of the workpiece is in contact with the upper turret member, the press working is prevented from being continued on the workpiece so that the upper turret member or the like which is a constituent element for the punch press can be suppressed from being injured, and the workpiece is prevented from being caught between the upper turret member and the lower turret member so that working. efficiency can be improved.
According to a second aspect of the present invention, as it depends from the first aspect, there is provided a punch press further comprising: control means for performing control so as to stop driving of the striker ascending/descending means and the carriage moving means when it is detected by the touch detecting unit that the first conductive wire and the second conductive wire have been made conductive to each other.
In the punch press according to the second aspect, when it is detected by the touch detecting unit that the first conductive wire and the second conductive wire have been made conductive to each other, a control is performed by the control means so as to stop driving of the striker ascending/descending (driving) means and the carriage moving means.
In this connection, under the state where a portion of the workpiece is in contact with the upper turret member, the press working is securely prevented from being continued on the workpiece, so that the effect obtained according to the first aspect can further be improved.
According to a third aspect of the present invention, as it depends from the first or the second aspect, there is provided a punch press wherein: the upper turret member is constituted by a rotatable upper turret; the lower turret member is constituted by a rotatable lower turret; and turret rotating means for rotating the upper turret and the lower turret in synchronism with each other is provided in the punch press.
In the punch press according to the third aspect, the upper turret and the lower turret are rotated in synchronism with each other by driving of the turret rotating means before the striker is descended by the striker ascending/descending means, so that a predetermined punch and a predetermined die can be positioned in a working area.
According to a fourth aspect of the present invention, as it depends from one aspect among the first aspect to the third aspect, there is provided a punch press further comprising: control means for performing control so as to stop driving of the striker ascending/descending means, the carriage moving means and the turret rotating means when it is detected by the touch detecting unit that the first conductive wire and the second conductive wire have been made conductive to each other.
In the punch press according to the fourth aspect, when it is detected by the touch detecting unit that the first conductive wire and the second conductive wire have been made conductive to each other, a control is performed by the control means so as to stop driving of the striker ascending/descending (driving) means, the carriage moving means and the turret rotating means.
Therefore, under the state where a portion of the workpiece is in contact with the rotatable upper turret (the upper turret member), the press working is securely prevented from being continued on the workpiece, so that the effect obtained according to the first aspect can further be improved.